1. Technical Field
The present invention relates to an optical fiber light source apparatus in which light is emitted from an optical fiber, and a discharge lamp serves as a light source, and particularly relates to an optical fiber light source apparatus having a concave reflection mirror in which a discharge lamp is built.
2. Related Art
An optical fiber light source is known, in which radiation light from a discharge lamp is condensed by a concave reflection mirror, and the condensed light is guided to the outside by an optical fiber, so that a workpiece may be irradiated therewith. For example, refer to Japanese Patent Application Publication No. 2010-040340. A schematic view of such known technology is shown in FIG. 6. A light source 31, which is made up of a discharge lamp 32 and a concave reflection mirror 33 for condensing light from the discharge lamp 32, is arranged inside a casing 30. A light guiding unit 34 is arranged on a light emitting side of the light source 31, that is, a side of an opening of the concave reflection mirror 33, and a light receiving end portion 35a of an optical fiber 35 is arranged on a light emitting side of the light guiding unit 34. The concave reflection mirror 33, the light guiding unit 34, and the light receiving end portion 35a of the optical fiber 35 are arranged so that the optical axes thereof are aligned with one another. Light emitted from the discharge lamp 32 is condensed by the concave reflection mirror 33, and the condensed light passes through the light guiding unit 34 so as to enter the light receiving end portion 35a of the optical fiber 35.
Replacement of such a discharge lamp used for the light source apparatus is required at the end of its life span. In such case, the discharge lamp and the concave reflection mirror are replaced together as a module in order to make replacement easy. The discharge lamp and the concave reflection mirror are taken out together by opening an opening-and-closing door provided in the casing, and thus the replacement can be performed easily (the discharge lamp may then be removed from the concave reflection mirror once they are outside the casing). However, although it is possible to arrange the lamp and the reflection mirror in advance so that optical axes thereof are aligned with each other, if replacement of such a lamp is repeated, the optical axis of the replaced lamp and those of the light guiding unit and the fiber light receiving end are shifted from each other, so that the luminance of the light emitted from the optical fiber decreases.
Although such an optical fiber light source apparatus is initially configured so that the second focal point of the concave reflection mirror may be located at a light receiving unit end surface of the optical fiber, the position of the lamp and that of the reflection mirror are shifted from each other every time such a lamp is replaced, so that the position of the second focal point of the reflection mirror also shifts therefrom, whereby the condensing efficiency with respect to the optical fiber decreases. Since such an optical fiber is very thin, it is necessary to position them with sufficient accuracy in order to position the second focal point of the concave reflection mirror with respect to the end surface of the optical fiber. It is desired that an operator, who performs replacement of such lamp, can attach it easily and precisely without being concerned about positioning the lamp.